1. Field of Invention
The present invention relates to a deposition system and a method of operating thereof, and more particularly to a deposition system for atomic layer deposition.
2. Description of Related Art
Typically, during materials processing, when fabricating composite material structures, plasma is employed to facilitate the addition and removal of material films. For example, in semiconductor processing, a dry plasma etch process is often utilized to remove or etch material along fine lines or within vias or contacts patterned on a silicon substrate. Alternatively, for example, a vapor deposition process is utilized to deposit material along fine lines or within vias or contacts on a silicon substrate. In the latter, vapor deposition processes include chemical vapor deposition (CVD), and plasma enhanced chemical vapor deposition (PECVD).
In PECVD, plasma is utilized to alter or enhance the film deposition mechanism. For instance, plasma excitation generally allows film-forming reactions to proceed at temperatures that are significantly lower than those typically required to produce a similar film by a thermal CVD process that thermally heats the process gas (without plasma excitation) to temperatures near or above the dissociation temperature of the process gas. In addition, plasma excitation may activate film-forming chemical reactions that are not energetically or kinetically favored in thermal CVD. The chemical and physical properties of PECVD films may thus be varied over a relatively wide range by adjusting process parameters.
More recently, atomic layer deposition (ALD) and plasma enhanced ALD (PEALD) have emerged as candidates for ultra-thin gate film formation in front end-of-line (FEOL) operations, as well as ultra-thin barrier layer and seed layer formation for metallization in back end-of-line (BEOL) operations. In ALD, two or more process gases, such as a film precursor and a reduction gas, are introduced alternatingly and sequentially while the substrate is heated in order to form a material film one monolayer at a time. In PEALD, plasma is formed during the introduction of the reduction gas to form a reduction plasma. To date, ALD and PEALD processes have proven to provide improved uniformity in layer thickness and conformality to features on which the layer is deposited, albeit these processes are slower than their CVD and PECVD counterparts.